Screens are used in the aggregate business for separating rock, crushed rock, gravel, sand, and the like (herein referred to as “material”) into various sizes. Screens typically comprise one or more screen decks containing a perforated screening medium that acts as a sieve, through which the material is separated. A charge of material is deposited on the receiving end of the screen deck and, as the material is conveyed to the discharge end, smaller material falls through the openings, leaving the larger material retained on the screen deck.
Screens generally use a vibrating mechanism to assist in the separation process, as well as in the conveyance of the material towards the discharge end. The assembly typically includes a screen box having a screen deck and a common frame. Generally, the screen box is vibrated by a vibrating mechanism that is coupled to the common frame. The vibratory motion promotes stratification in the material bed, bringing the smaller material down to the screening medium surface to pass through the openings.
Vibrating mechanisms may be characterized by the form of the vibration and the number of bearings used in the mechanism. Vibrating mechanisms may produce motions that include circular, elliptical, and straight-line reciprocal movement. For example, a suspended double eccentric screen utilizes a counter weight on a shaft to vibrate the screen box, and consequently the screen deck, in a circle-throw motion. The material is propelled toward the discharge end by the motion of the vibrating mechanism.
Typically, the screen box for a suspended double eccentric screen is isolated from the support structure by coil springs, rubber buffers, or shear rubber mounts. Such support systems are costly and require a great deal of space, which may restrict maintenance access. In addition, such mounts generally have a high tolerance in shear rates and do not sufficiently restrict lateral movements that can damage machinery components such as bearings and shafts. Further, conventional springs often break in corrosive environments and on overloading. Therefore, there is a need for a screen and support system that allows a more cost-effective design, is easier to maintain, requires less space, has a longer service life, and restricts lateral movements in the support system.
Additional information will be set forth in the description that follows, which will be obvious in part from the description or may be learned by practice of the invention.